I think the post has been carried away and has missed the point of the original post.
Let's suppose for a moment that SBF et al. are correct and the Tetragrammaton or some version of it was indeed in the New Testament, but the original NT was hopelessly lost and we only have "corrupt" 2nd century and beyond Greek manuscripts of the NT.
Ok, so... WHERE in the "original, uncorrupted" NT did the Tetragrammaton appear?
In EXACTLY the 237 times that it appears in the New World Translation?
Why not 238 times?
Why, for example, did the NWT not translate THIS particular "Lord" as "Jehovah"?
(Acts 19:10) 10 This took place for two years, so that all those inhabiting the [district of] Asia heard the word of the Lord, both Jews and Greeks.
They had everything needed to translate it as such:
It is a phrase that is usually associated with "Jehovah", not "Jesus"...
As shown in the NWT, in the same book:
(Acts 8:25) 25 Therefore, when they had given the witness thoroughly and had spoken the word of Jehovah, they turned back to Jerusalem, and they went declaring the good news to many villages of the Sa·marʹi·tans.
They have had to retroactively imply that the "Lord" in Acts 19:10 is "Jehovah":
*** bt chap. 20 p. 161 par. 11 “Growing and Prevailing” Despite Opposition ***11 Paul may have spoken in that school auditorium daily from about 11:00 a.m. until about 4:00 p.m. (See study note on Acts 19:9, nwtsty.) Those were likely the quietest but hottest hours of the day when many stopped their work to eat and rest. Imagine if Paul followed that rigorous schedule for two full years, he would have spent well over 3,000 hours teaching. Here, then, is another reason why the word of Jehovah kept growing and prevailing. Paul was industrious and adaptable. He adjusted his schedule so that his ministry met the needs of the people in that community. The result? “All those living in the province of Asia heard the word of the Lord, both Jews and Greeks.” (Acts 19:10) What a thorough witness he gave!
What if the Witnesses didn't "restore" that one "Jehovah"? Are they guilty of not respecting Jehovah's name sufficiently, and acting like the "evil" sopherim who changed "Jehovah" for "Lord" 134 times?
SBF et al rely on George Howard's study to say that the "original" LXX and the "original" NT may have had the Tetragrammaton... but Howard's study at best allows for the possibility of the Tetragrammaton being in quotes of the OT...
Ok, but again I ask, WHERE? WHICH ONES? All of them?
ALL of them?
Then that would mean that Hebrews 1:10, 1 Peter 2:3, and possibly others, had "Jehovah" in them.
Hebrews 1:8-12 would then read:
(Hebrews 1:8-12) . . .But about the Son, he says: ... 10 And: “At the beginning, O Jehovah, you laid the foundations of the earth, and the heavens are the works of your hands. 11 They will perish, but you will remain; and just like a garment, they will all wear out, 12 and you will wrap them up just as a cloak, as a garment, and they will be changed. But you are the same, and your years will never come to an end.” And if you think about it, many of the quotes from the OT that do have "Jehovah" in them in the NWT actually help the trinitarian point of view.
(Matthew 3:3) . . .This, in fact, is the one spoken of through Isaiah the prophet in these words: “Listen! Someone is crying out in the wilderness, ‘Prepare the way of Jehovah, YOU people! Make his roads straight.’”
(Mark 1:1-4) . . .The] beginning of the good news about Jesus Christ: 2 Just as it is written in Isaiah the prophet: “(Look! I am sending forth my messenger before your face, who will prepare your way;) 3 listen! someone is crying out in the wilderness, ‘Prepare the way of Jehovah, YOU people, make his roads straight,’” 4 John the baptizer turned up in the wilderness, preaching baptism [in symbol] of repentance for forgiveness of sins.
Who actually walked the Earth? Jesus, or Jehovah? Why then were "Jehovah's" roads made straight, if Jesus walked them?
What about the "rule" that Kyrios, when used without the definite article, is grammatically like a name?
That would imply that Luke 2:11 says that "Jehovah the Christ" was born. Which is why many of the J versions translate it exactly like that!
So again... careful what you wish for!
Every single "rule" you come up with will have sufficient cases where it identifies Jesus as Jehovah, and so my take on this is that EVEN IF we find ONE manuscript proving that the NT had the Tetragrammaton in it, odds are, that it will have a text that goes against the Witnesses... and even then, supposing we do find a spot where it agrees 100% with the Witnesses, what about the other 236 occasions? What manuscript evidence will you have for or against it?
But right now, as the evidence stands, there is nothing in the manuscripts to indicate that the Tetragrammaton was in the original, and so the Watchtower has to rely on very circumstantial evidence that can go either way and can be interpreted in both ways... and relying on J versions which are wildly more trinitarian than any other NT that does NOT have "Jehovah" in it!
Even when you do find the VERY few J versions which aren't trinitarian, these J versions differ in opinion with the NWT as to whether a specific instance of "Lord" is "Jehovah" or "Lord".